Now What I did:
5. Add a new menu item extension with a corresponding command that should open the help system
6. What should happen when the button is pushed, is actually taken from the helpSupport example in the FAQ (sourcecode from the RapHelpSupport.zip -> RAPHelpUI)
7. If I now press the button in the application (started from eclipse with jetty), it will not open anything except the shell and "index.jsp missing, 404".

My question here is, hw do I have to modify the "getBaseUrl" method, so that it finds the content?

Furthermore, does the help window, that will be opened look like the help in eclipse (with the search, etc) ?

In our shop, we have successfully integrated the Eclipse Help base and UI in our software. We have context help and full help system capabilities. Unfortunately it requires some modifications to the help bundles to make them RAP compatible. At some point I will release this in full to the RAP incubator, but it needs some more refinement first. I suppose for now I could provide a patch of the current state in a bug report. Would you open a bug for full help system support on the incubator?